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HoTat2 said:
Although for some strange reason, I read in a D* tech bulletin about the SWiM-16 awhile ago, the exact edition I can't remember at the moment. That cascading two of them this way was not yet recommended. :confused:

Never could figure out why, or if that advisory was ever since officially rescinded.
Yes there was "some story" about not doing this, but it works and does look to be "by design".
Some of the tech bulletins make me wonder.
One of these was about the HR20-100 & DECA.
Engineering had us in the test group use a splitter behind the DECA so it would power the DECA off the SAT #2.
Then a "tech bulletin" came out moving the splitter to in front of the DECA, connecting the DECA to SAT $2, which also required a BSF on SAT #1.
This really doesn't make any sense as it requires a BSF that wasn't needed before, and doesn't change anything.


 

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HoTat2 said:
BTW, happened to stumble across the particular "Technical Bulletin with points against cascading SWiM-16s highlighted. As to why is anyones guess.

Sorry for posting it to this thread somewhat belatedly :D

Issue 5 2011 - 4.25.11
"Any yet" it's been done for over a year without any problems, Earl is doing it, and is done in MDU systems. :shrug:

These are the same folks who took this:


And issued a bulletin turning it into this:


Now, I'll ask ANYONE what the difference is other than requiring a BSF that the first didn't. :nono:
 

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HoTat2 said:
It appears when this TB was written for some reason they didn't (yet anyway) recommend use of the legacy ports due to a perceived "high (internal) signal loss" between the 4-6 satellite inputs and the legacy port outputs.
This brings up the question [that I don't have the answer for] of where's the AGC in the SWiM?

A) If it's on the output, then the legacy [or cascade as they're called on the SWiM-32] ports are low, since these have been measured with -30 dBm input to have -40 dBm output.
This would mean as the input drops even further, that the legacy ports would be "in the dirt" fairly quickly.
SWiM reaches full gain by -45 dBm to maintain the -30 dBm output of the SWiM.

B) If it's on the input, then the legacy/cascade ports are also regulated by the AGC, and with -40 dBm, the second SWiM adds the 10 dB through its AGC to the SWiM output for it to have -30 dBm, with have another 5 dB for any extra cable loss.

With A, those that have been running them cascaded, should have been seeing 771a errors with moderate rain, on the receivers connected to the second SWiM.

With B, both SWiMs have the same range of output power, as the first SWiM regulates the power for rainfade control, while the second compensates for the loss of the legacy/cascade ports.

Now anyone that has a SWiM-16 and a meter that measures power, let me know and I'll give you some tests to run to see where the AGC is.
 
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